BIOLOGY 1A03 - Theme 3 - Applied Lecture - Module 1 & 2

what enzyme breaks down lactose?

lactase

where is lactose located in the absorptive intestinal enterocyte cells?

apical surface

weaning dairy products causes a(n) ________________ in the production of lactase and the expression of the corresponding gene.

decreases

About ______% of humans have a reduced ability to digest lactose after weaning

65

mutations along what gene results in enhanced lactase gene transcription?

MCM6

populations that have a high frequency in their ability to digest lactose?

>90% of swedes, danes and pastoralist populations from africa and around 50% of spanish, french and pastoralist arabs

lactose intolerance

the inability of an individual to digest lactose is caused bu the inability to express the lactase gene, which causes excess lactose to accumulate in the small intestines, attracting water molecules, disrupting eater uptake into the blood stream, intestinal bacteria acts on lactose and causes the signs

signs and symptoms of lactose intolerance

gas, bloating, cramps, nausea and diarrhea

what gene codes for the lactase enzyme?

LCT gene

where is the LCT gene located?

chromosome 2

what does a LCT gene mutation cause?

congenital lactase deficiency

what type of gene mutation is common on the LCT gene?

single amino acid mutation

galactosemia

galactose in the blood

what mutations along chromosome 9 cause galactosemia?

mutation of GALT, GALE and GALK1

what type of mutation of chromosome 9 is associated with galactosemia?

single amino acid mutation

what does galactosemia cause?

toxic accumulation of galactose in the blood leading to organ and tissue damage

common signs and symptoms of galactosemia

vomiting, diarrhea, jaundice and cataracts

treatment for lactose intolerant patients

omit lactose, only consume pre-treated milk with purified lactase in it

treatment for galactosemic patients

omit galactose